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    万盼, 刘灵, 赵中华, 王千雪, 胡艳波, 王宏翔, 惠刚盈. 沙地樟子松天然林林木大小分布特征[J]. 北京林业大学学报, 2017, 39(7): 1-9. DOI: 10.13332/j.1000-1522.20170132
    引用本文: 万盼, 刘灵, 赵中华, 王千雪, 胡艳波, 王宏翔, 惠刚盈. 沙地樟子松天然林林木大小分布特征[J]. 北京林业大学学报, 2017, 39(7): 1-9. DOI: 10.13332/j.1000-1522.20170132
    WAN Pan, LIU Ling, ZHAO Zhong-hua, WANG Qian-xue, HU Yan-bo, WANG Hong-xiang, HUI Gang-ying. Distribution characteristics of tree size of Pinus sylvestris var. mongolica nature forest on sandy soil[J]. Journal of Beijing Forestry University, 2017, 39(7): 1-9. DOI: 10.13332/j.1000-1522.20170132
    Citation: WAN Pan, LIU Ling, ZHAO Zhong-hua, WANG Qian-xue, HU Yan-bo, WANG Hong-xiang, HUI Gang-ying. Distribution characteristics of tree size of Pinus sylvestris var. mongolica nature forest on sandy soil[J]. Journal of Beijing Forestry University, 2017, 39(7): 1-9. DOI: 10.13332/j.1000-1522.20170132

    沙地樟子松天然林林木大小分布特征

    Distribution characteristics of tree size of Pinus sylvestris var. mongolica nature forest on sandy soil

    • 摘要: 分析内蒙古红花尔基沙地樟子松天然林直径和树高的一元和二元分布特征,以期为该区樟子松天然林进行抚育经营等提供科学依据。在内蒙古呼伦贝尔沙地南段的樟子松天然林中设置2块100 m×100 m的不同密度(940和1 149株/hm2)方形固定样地,按整体和分层的方法,对样地的林分直径和树高的变化规律及两者之间的关系进行研究。结果表明:1)2块样地林木的最大、最小直径及平均直径相等;低密度林分直径分布较分散,高密度林分则分布较集中。2块样地上、下层林木的平均直径均基本相同;低密度林分上层木直径分布为正态,下层木则左偏;高密度林分上层木直径分布左偏,下层木则为正态。高密度林分的平均树高大于低密度林分,但高大林木比例较低密度林分低;高密度林分上层木平均树高也大于低密度林分,且高大林木比例也较低密度林分高;而高密度林分下层木平均树高和高大林木比例均较低密度林分高。2)低密度林分中小径级林木株数比率小于大径级林木株数比率,高密度林分中则相反;低密度林分中小径级林木的林木树高与胸径的比值大于大径级林木的林木树高与胸径的比值,高密度林分中无明显差异。2块样地上层木小径级林木株数比率均小于大径级林木株数比率,其林木的树高与胸径在大、小径级中的比值也无明显差异;低密度林分下层木中小径级株数比率大于大径级林木株数比率,高密度林分则相反;2块样地下层林木在小径级林木中的树高与胸径比值均明显大于在大径级林木中的树高与胸径比值。可见,高密度林分的平均树高均大于低密度林分;高密度林分直径分布相对集中,低密度林分直径分布分散,从而造成不同密度的天然樟子松林林分平均直径无明显差异。低密度林分中大径级林木株数的比率要比高密度林分高;密度的不同也导致了林木径向和纵向生长的差异。因此,针对密度大的樟子松天然林分应适当疏伐,降低密度,减少种内竞争;而对密度小的林分应适当进行土壤植被管理,促进林下天然更新。

       

      Abstract: This study aims to analyze the univariate distribution and bivariate distribution characteristics of DBH and height of Pinus sylvestris var. mongolica nature forests on sandy land at Honghuaerji of Inner Mongolia of northern China in order to provide scientific basis for their sustainable forest management. Two 1 ha Pinus sylvestris var. mongolica nature forest plots with different densities(940 and 1 149 plant/ha) were established and all trees with DBH>5 cm were investigated. Density distribution characteristics of DBH and height and their bivariate distribution were analyzed on whole stand level and on different categorized tree height size classes, and the statistical calculation was implemented in R language software. The results showed that:1) on the whole stand level, the distributions of DBH and height of tree in two plots generally showed double-peak curve. The average DBH in plot 1 and plot 2 was basically the same while average height in plot 2 was greater than plot 1, but number of large size class trees both in terms of DBH and height in plot 1 was greater than plot 2. Analysis based on different categorized height layers showed that distributions of DBH and height of overstory trees were unimodal distribution in both plots and distribution of DBH in plot 1 was normal distribution. Average diameter of overstory trees in both plots was basically the same but average height of overstory trees in plot 2 was greater than plot 1, and number of overstory trees in plot 1 was more than plot 2. Additionally, distributions of DBH and height of understory trees in two plots showed unimodal distribution and the distribution of DBH in plot 2 was normal distribution. Average diameters of understory trees in plot 1 and plot 2 were basically the same but average height of understory trees in plot 2 was more than plot 1, and large trees of overstory trees in plot 2 were also more than plot 1. 2) The bivariate distributions of DBH and height in two plots were multi-peak distribution. Overall, the ratio of large tree size class was more than small tree size class in plot 1, but this situation was opposite in plot 2. Meanwhile, the ratio of height to DBH of large tree size class was less than small tree size class in plot 1, but the ratio was almost the same in plot 2. From different height layer analysis, the ratio of large tree size class was more than small tree size class among overstory trees in the two plots, and the ratio of height to DBH of overstory trees was not significantly different between large and small tree size classes. The ratio of large tree size class was greater than small tree size class among understory trees in plot 1, but this situation was opposite in plot 2, and the ratio of height to DBH of large tree size class was less than small tree size class of underwood in the two plots. Stand density had no obvious effect on average diameter in Pinus sylvestris var. mongolica nature forests. High density can elevate the growth of tree height of whole stand, but number of dominant trees of whole stand decreased in high density stand, especially for overstory trees. In the meanwhile, stand density had effect on the distribution of energy in the radial and longitudinal growth of trees, and the biomass was always distributed to tree height growth in the high density stand. Therefore, high density forest should be properly thinned in order to decrease intertree competition, which can allocate tree biomass reasonably and improve the proportion of dominant trees in whole stand. For low density stands, the forest should be taken properly above story thinning in order to improve the growth of understory trees.

       

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